The casting announcement is doing its job, especially for the mainstream. Even those who may have issues with an all-black cast are probably curious on how this ensemble will fair. The talent pool on this one is pretty damn high.
As for expectations for the film, gotta temper them. I know some are hoping for some revolutionary shyt, but in the end, its an MCU film owned by Disney. Only so much glorious shyt they'll put. We should just hope for, at the least, a solid film with solid portrayals across the board. Anything beyond that is a bonus.